1. Technical Field
This present invention pertains to electronic packaging technology, and more particularly, to the packaging of modules comprising electronic devices mounted on a substrate disposed under a cap or cold plate.
The high circuit densities in modern integrated circuit devices require that the heat generated by their operation be efficiently removed in order to maintain the temperature of the devices within the limits that will keep the operating parameters of the devices in a predetermined range, and also prevent the destruction of the device by overheating.
Cooling of electronic devices can be achieved by immersing the devices in a suitable liquid coolant. However, these cooling techniques can result in corrosion of the device and substrate metals, and also present rework problems. Another type of cooling known as thermal conduction cooling provides a conducting link of material between the device and the cap or cold plate.
In thermal conduction type cooling system, it is important to maintain a hermetic seal and sealing force between the substrate and the cooling cap to prevent the corrosion of the electronic devices and the interconnect circuitry. Moreover, because of the ambient atmospheric temperature between the electronic devices on the substrate and the cap or cold plate, the atmosphere becomes highly humid. Gases such as nitrogen or helium may be introduced at a predetermine pressure during assembly so as to maintain a dry atmosphere after the assembly is sealed. Such a sealed system enhances the reliability of the circuitry and deterioration is prevented.
This invention is an improved method to seal and assemble thermal conduction type cooling systems.
2. Background of the Invention methods to seal and assemble of thermal conduction type cooling systems.
U.S. Pat. No. 4,949,219 issued Aug. 14, 1990 to Moriizumi et al. for "Module Sealing Structure" discloses a polimide layer formed on the surface on the substrate and a metallic conductor layer formed on the polyimide layer. The seal is secured using mechanical fasteners such as screws.
U.S. Pat. No. 4,999,741 issued Mar. 12, 1991 to Tyler for "Package in the Heat Dissipation of Electronic Devices" discloses a thermally conducting flexible membrane capable of being urged into thermal contact with an electronic device producing a simple hermetic seal as well as contact with the electronic device.
U.S. Pat. No. 4,514,752 issued Apr. 30, 1985 to Engel et al. for "Displacement Compensating Module" discloses a blocking article, such as polyimide tape, for inhibiting movement of an epoxy composition into a gap area during manufacturing of a thermal conduction cooling assembly.
U.S. Pat. No. 4,685,211 issued Aug. 11, 1987 to Hagihara et al. for "Method of Producing a Cooled Electronic Assembly" discloses a cooling plate assembly secured by mechanical fasteners such as screws.
U.S. Pat. No. 4,914,812 issued Apr. 10, 1990 to Webster for "Method of Self-Packaging an IC Chip" discloses a method of self packaging an integrated chip on a printed circuit board where the conductive leads form an electrical connection with interconnect leads on the printed circuit board.